Approximately 4250 patients have undergone operation for acquired and congenital heart disease in this clinic. Pre- and postoperative hemodynamic, clinical assessment and long term follow-up has generated considerable data concerning survival, complications, and functional improvement following cardiac operation. Individuals who have undergone single or multiple valve replacement (in approximately 1100); mitral or aortic commissurotomy (in approximately 450) or coronary artery bypass grafting (in approximately 100) have been entered into a computer based program for the purpose of record keeping and analyses of survival, quality of life and complication following operation. The records are updated with each outpatient visit, hospital admission, or communication with either patient or physician. If a patient fails an appointment for a period of greater than 90 days, his name is automatically selected by the computer for more extensive follow-up. Life survival curves and histograms for the various cohorts of patients can now be directly plotted by the computer program. Causes of death, incidence of thromboembolism, anemia hepatitis, or prosthetic dysfunction can also be retrieved in tabular form for any specific series of valves or particular operation. Multiple other studies have utilized this computer based program for hemodynamic incidence of complications, or long term follow-up data of various groups of patients who have undergone a cardiac operation.